It is well known that fluid can be infused directly into wall of a blood vessel to treat some ailments. For example, medicaments can be administered into an arterial wall to inhibit or prevent the restenosis of plaque in the artery.
Due to the toxic nature of some fluids, the procedure must insure that only minimal amounts of medication are washed away into the blood stream and not actually infused into the vessel wall. Thus, the device for administering the fluid into the arterial wall must be easy to use, accurate and reliable.
Several devices have been suggested for the purpose of infusing fluid directly into a vessel wall. For example, a device for medicating a vessel wall is disclosed in U.S. Pat. Nos. 5,112,305 and 5,242,397 which issued to Barath et al. Specifically, the device disclosed in the Barath et al. patents employs a balloon which initially is slowly filled with a medicament to expand the balloon and position the balloon's surface against the vessel wall. Subsequently, the balloon is rapidly filled. The rapid filling of the balloon reconfigures tubular extensions on the surface of the balloon for insertion into the vessel wall and infusion of medicaments through the tubular extensions.
However, this device has proved not to be entirely satisfactory. Specifically, with this device, the mechanism for infusing a fluid into a vessel wall is not independent and separately operable from the mechanisms which position the device in the artery and which cause penetration into the vessel wall. Further, this device does have the capability of selectively applying a variable force to the fluid injectors of the device as they penetrate into the vessel wall.
In light of the above, it is an object of the present invention to provide a device for injecting fluid into a wall of a vessel having a mechanism for penetrating the vessel wall that is separate from the mechanism which injects the fluid into the vessel wall. It is another object of the present invention to provide a device for injecting fluid into the wall of a vessel which can selectively vary the force that is used to penetrate the vessel wall. Still another object of the present invention is to provide a device for injecting fluid into the wall of a vessel which is easy to use, and relatively simple and inexpensive to manufacture. Yet another object of the present invention is to provide a device for injecting radioactive isotopes into a wall of a vessel.